Lagging issues when moving between records

Good afternoon. We are experiencing an issue on V21 where users find the system sometimes has a 'lag' when moving between records. i.e the new record will still show the previous records DOB/phone number/e-mail etc (or possibly the same Note/History if they were on that tab) Is there a reason for this happening and is there a fix/workaround to prevent this from happening? It is causing our advisers to potentially use the incorrect information on correspondence. All assistance would be greatly appreciated!